Internal combustion engine



1942. b. HENNING- 1 I INTERNAL COMBUSTION ENGINE I Original Filed Nov.17, 1931 5 Shets-Sheet 1 FIG/a.

y I 01. M

2, 1942. O.HENNING 2,306,251

INTERNAL COMBUSTION ENGINE Original Filed Nov. 17, 1931 5 Sheets-Sheet".2

Dec. 22, 1942. 0.. HENQNING 2,306,251

INTERNAL COMBUSTION ENGINE Original Filed Nov. 17, 1951 E ShetS-Sheet s0m HE/V/W/VG A TfoR ygy 319 32. 0. HENNING I ZBGQZSE INTERNAL COMBUSTIONENGINE Original i iled Nov. 17, 1931 5 Sheets-Sheet 4 0770 HE/VN/NQmum-mum" GMAM' Dec. 22, 1942. o. HENNING 9 3 INTERNAL COMBUSTION ENGINEOriginal Filed Nov. 17, 1931 5 Sheets-Sheet 5 0770 HE/y/V/A/ .4 Tram 67Patented Dec. 1942 UNITED STATES 'PATEN 1* OFFICE mramva COMBUSTIONEnema Otto Kenning, St. Louis County, Mo., assignor, by

mesne assignments, to Carter Carburetor Corporation, St. Louis, Mo., acorporation of Dela,-

ware

Original application November 17, 1931, Serial No. I 575,577. Dividedand this application November 13, 1941, Serial No. 418,980

23 Claims. (01. 123-119) This invention'relates to carburetors forinternal combustion engines, and more particularly to carburetors of theplain tube type. That is to say, the type in which the air and fuelinlets are of constant size regardless of suction during normaloperation of the carburetor, at

normal operating temperatures. a

This application is a division of my co-pending application, Serial No.575,577, flied November 17, 19.31. I

It is an object of this invention to provide a carburetor having new andimproved means for automatically changing the operation thereof as theengine warms up or cools off, so that during the low temperatureoperationof the carburetor, such operation will embody at least some ofthe principles of the air valve carburetor,

while atnormal and high temperatures the carburetor will be operatedstrictly on the plain tube principle. I

It is a further object of this invention to'provide a carburetor inwhich fuel mixture ratio is automatically controlled both by temperatureand suction, so that the mixture will be leaned out at high temperatureand also at high suction.

provide means for varying the position of said.

choke valve in accordance with the suction in the intake manifold ofsaidengine.

It is a further object of this invention to-provide a carburetor havinga choke valve controlled by a thermostat and to provide means forlimiting the tension to which said thermostat is subjected under hightemperature conditions.

The invention will be better understood from th following descriptionand the accompanying drawings, referring to which:

Figure 1A is a diagram of the carburetor according to my invention.-

Figure 1 is a somewhat diagrammatic view I showing an elevation of thecarburetor with parts in section, and showing a section of the exhaustFigure 5 is a sectional view oi the carburetor shownin Figure 1, thesection being taken through the float bowl and accelerating pump.

Figure 6 is a plan view .of the carburetor shown in Figures 1 to 5.

Figure 7 is a detail view showing fled form of the device.

The reference numeral I indicates the lower half, or main body member ofthe carburetor."

This lower half is provided with a flange 2 by means of which it may beattached to the intake manifold of aninternal combustion engine. Theupper half of the carburetor 3 is formed in a separate casting andsuperposed on the lower half. The two halves of the carburetor have adowndraft mixing conduit through, which mixing. conduit comprises airinlet. 5, air chamber 6, mixing chamber I, and discharge outlet 8.

The admission 'of air to the carburetor is controlled by a choke valve,which is generally indicated at 9, and which is carried by the shaftIll. The choke valve is made up of'two sections, one section being.rigidly attached to the choke valve shaft, as indicated at H, and theother section l2 being pivotally attached to the choke valve shaft andoperable by suction. A spring mounted on the solid section II and has alatch contact member l6 thereon for contacting with the wall of the airinlet, and projection H at the other end thereof for contacting with theprojection H to limit the opening movement of the valve portion l2. Theconstruction and operation of this valve is shown and claimed in PatentNo. 1,894,354 to Kommer and 'Hennlng, issued January 17, 1933.

The fuel is supplied to the mixing conduit through a nozzle l9 andnozzle tip 20, whichnozzle tip is formed integral with the primaryventuri 2|. a secondary venturi 22, and the secondary venturi dischargesinto the 'main venturi 23, as indicated in Figure 1. The discharge oifuel mixture from the carburetor is controlled by throttle va1ve'23,which i pivotally carried on shaft 24, and the shaft is arranged formanual operation in any convenient manner.

Fuel for low speed operation is supplied to the mixing conduit throughport or nozzle 25. This discharge outlet is shown in Figure '1 as asingle port extending to both sides of the throttle when same is inclosedposition. but it will be undera-slightly modl extending there- Theprimary venturi discharges into' stood that any other port constructionor arrangement may be used if desired.

Fuel is supplied to the nozzle 25 by means of idle tube 26, connectingpassageways 21-28, calibrated passageway 29, passage 30, and meteringJet 3|. Fuel for the main nozzle is is also supplied from jet 3|,passage 30,- and the chamberi I: which surrounds tube 28. Thus, it willbe seen 1 that the main nozzle is and idling nozzle 25 are connected-byrestricted passagewaygzfl and both nozzles receive their fuel in commonfrom the jet ll, which is controlled in accordance with the position ofthe throttle by means of metering rod a. The jet 3| takes its fuel fromthe chamber II in which the fuel is maintained at a constant level A-Aby float 3i and needle valve 36. It may be noted at this point thateither the float valve 36 or the lip 35a, whichoperates the float valve,may be chromium plated to prevent wear. Fuel is supplied in aconventional manner to needle valve 38 through connection I! by theusual fuel pump or gravity tank.

The acceleratingpump piston 38 is operated I by means of a rocker arm "aconnected to the throttle through link 38 and operating arm 40. Asuitable vent ll is formed in the upper part of the float chamber abovefuel level for connecting said float chamber to the inside of the mixingconduit. i I

Additional venting means for the float chamber, comprising an orifice 42is also provided.

and socket joint I, and link 8. to an arm 51 which is mounted on thechoke shaft, The arm is mounted to freely rotate on the choke shaft, buta stop It is provided to contact with an. extension 59 onthe arm 41, sothat movement of the arm I! in a clockwise direction with reference toFigure 1 will cause an opening movement of the choke valve.

A spring 60 is mounted in the cylinder 52 for normally holding thepiston 53 in its raised position, so that, the normal closing of thechoke valve under the influence of the thermostat 42 will not beinterfered with. A suction passage ii is formed in the lower casting Ito connect the discharge outlet of the carburetor with the lower' end ofthe cylinder through a restricted orifice-i2. The restriction of theorifice I2 is calibrated to provide a delayed action in the Preferably,the orifice 42 is of smaller capacity than the orifice 4|, whereby adraft will be created through the float chamber for cooling the fueltherein, but the fuel in the fioat chamher will also be subjected to asuction corresponding to the speed of air flowing through thecarburetor.

The choke valve 9 is primarily controlled by thermostat 43, which ismounted on the exhaust pipe 44 of the engine. The thermostat is of theusual bimetallic type and is wound in such a manner that the free end I!will turn in a clockwise direction,'with reference to Figure 1, when thetemperature is raised. The connection of the thermostat to the chokevalve includes a link ll which is pivoted to the free end of thethermostat and also to the arm I! at pivot II. The link ll is providedwith a shoulder 49, and a spring II is mounted around the link 46 abovethe shoulder. so that one end of the spring will contact with theshoulder and the other with the pivot member 48. It will be understoodthat the rod is freely slidable in pivot 48 and its motion in onedirection is limited -by the spring, and motion in the other directionis limited by nut II which is fixed to the end of link ll.

Arm 41 in this modification is attached to the choke shaft I I; With thethermostat in the position shown in Figure 1, the choke valve will be inclosed position: as the thermostat heats opening of the choke valveunder the influence oi the suction, otherwise, the mixture would beleaned out too quickly when the engine starts to run under its ownpower. A valve ll slidab y mounted in the hollow piston rod It andnormally held in downward position by spring 84 is provided for closingoff the orifice I after a predetermined movement of the piston.

A modified form of the invention may be constructed as shown in Figure7. The arm 41 is loosely'mounted on the shaft it. The shaft I1 istightly mounted on the shaft 7 II and the valve 83 is omitted, thepiston 53, being relied on to give a full opening movement of the chokevalve under suction. It will be noted that the stop It is formed in twoportions at an angle to each other, the lower portion of this membercontacts with the projection 50 on one end of arm .41, and the upperportion contacts with the opposite end of the arm 41, permitting a lostmotion of approximately 30 degrees between contact of stood, of course,that extremely high temperaup, the choke valve moves to the postionindias soon as the engine starts to run under its own power, a cylinderI! having, a piston 88 slidably mounted therein is provided; The pistonis contures on the exhaust pipe are reached during operation of the car.These temperatures may reach 475 or 500 degrees Fahrenheit, and inasmuchas it is desired to have the choke valve fully opened by the thermostatat a temperature of approximately 150 degrees or less, thethermostat'would be placed under a considerable strain after the fullopen position was reached, if some means were not provided forpermitting free movement of the thermostat. The spring. II is normallymade weak enough to permit a substantially free movement of thethermostat. but when additional lost motion and free movement after thechoke valve is opened is provided for, the danger of straining themember 43 at high temperatures issubstantially eliminated.

The operation of the device is as follows:

Fuel is supplied from a conventional gravity tank or fuel pump to theconnection 31, and the admission of fuel to the float bowl I! iscontrolled by float valve 8! and float ll. The fuel is maintained at asubstantially constant level AA in the float chamber by thefloat-mechanism and is supplied'to the'nozxles'i! and II nected by meansof a hollow piston'rod [4. ball byon. It my be noted a I 01 a from thefloat chamber for both of these nozzles passes through the jet 8 I Whenthe engine is to be started cold, the

choke valve 9 will be in closed position, and the thermostat 4! will beapproximately in position shown in Figures 1 and 1a, therebyconcentrating the suction developed by the engine on the fuel nozzles 20and 25 (Figure 1), and

drawing a very rich mixture into the engine for starting.

1 It will be understood that the normal cranking speeds of an engine are100 R. P. M. or less, while the normal operating speeds are 200 R. P. M.or more. As soon as the engine begins to operate under its own power,the suction is very substantially increased. :The suction at crankingspeeds is approximately one-half pound per square inch, while atoperating speeds, the

suction with the ,choke valve in closed position will be six or sevenpounds per square inch.

As soon as the engine starts to run under its own power, the increasedsuction will slightly open valve portion l2 against the resistance ofthe spring I! until the movement of the member I2 is stopped by contactof the projection H with the latch ll andadmit some additional air tothe engine to slightly lean out the mixture.

At the same time that the engine starts to run under its own power, thesuction will be supplied to cylinder 52' by means of connection 4|, andwill begin to draw the piston 53 downwardly, and open the choke valve.As soon as the solid portion of the choke valve reaches the positionshown in Figure 3, the projection I! on the latch I5 will pass out ofcontact with projection I4 on the yieldable portion of the. valvepermitting portion I! of the choke valve to open further independentlyof portion ll under the influence of the intake suction, and thecarburetor may then operate as an air valve carburetor until thethermostat 43 has warmed up sufficiently to continue the openingmovement of the choke valve. a pause in the opening movement of saidvalve after the operation ofthe suction cylinder isv completed. Duringthis pause, the thermostat 43 is being warmed up, and the pistonchambers of the motor are also warming up. During this may rotateapproximately 30 degrees clockwise relative to shaft l0 and arm 51 rigidtherewith before the spring ill is compressed. In this modification,sufiicient movement of the piston 53 is permitted prior to the closingof the valve 83 to permit the suction to fully open the choke valve. Y

With the latter construction, closing movements of the choke valve willoccur whenever thesuction in the intake manifold is lowered, unless thetemperature is so high that the lost motion between the arm 41' and thestop 58 has already been taken up. This is very desirablefonacceleration when the temperature is comparatively i low, and it willbe noted that they partial closing of the choke valve in response tolowering of. the depression in thedischarge outlet of the carburetor iseliminated when the thermostat 43 is hot enough to move the arm 41 intocontact with.

stop 58. For instance, if the operating temperature of the thermostat is150 degrees with the choke valve fully open, the degrees of closingmovement would still be permitted when the suction drops. If thetemperature rises another 25 or 30 degrees, the arm 41 will be givenapproximately 10 degrees of angular movement in a clockwise directionwith reference to Figure 1.

If the suction now falls, the choke valve can only have 20 degrees ofclosing movement before contact of the stop 58 with the arm 41, andif'the temperature is still further raised by 40 or 50 degrees, thechoke valve will not close at all when It will be noted that there ispause, the portion I2 of the choke'valve, which is directly operated bysuction, takes care of the requirements of the carburetor and opens orthe exhaust pipe 44 has reached a temperature of approximately 150degrees, the choke valve will be in full open position, 0r nearly so.After the full open position of the choke is reached, further movementthereof is prevented by stop meansjs, as shown in broken lines in Figure'l, and further heating of the thermostat will cause compression of thespring 50. The strength of qthis spring is insufficient to causepermanent deformation of the thermostat at high temperatures.

In the second modification, as shown in Figure'l, the arm 41 is loose onthe choke shaft and the suction drops. Inasmuch as the normal operatingtemperature of the thermostat is approximately 250 or 300 degrees. itwill be seen that the choke valve will be kept in full open position fornormal operation, but under low temperatures and before the engine isfully warmed up, there will be a slight closing movement of the chokevalve to assist acceleration.

I claim:

1. In a carburetor for internal combustion engines, a downdraft airpassage, a throttle valve at the lower end thereof, a choke valve at theupper end thereof, said choke valve comprising a suction operatedportion and a solid portion, a shaft rigidly fixed to said solidportion, a piston connecting with said shaft, a cylinder for saidpiston, a connection for conveying suction to said cylinder from a pointin said air passage below said throttle, and a heat responsive deviceconstructed and arranged to act in opposition to the opening of thechoke valve'when the temperature is low.

2. In a carburetor, means forming a downdraft airpassageway, a chokevalve at the upper end of said passage, a throttle valve at the lowerend of said passage, a pair of fuel'nozz'les discharging by suction intosaid air passageway, one of said nozzles discharging at acomparativelylow level adjacent said throttle, and the other discharging at acomparatively high level between said throttle and said choke valve, a

suction operated piston for operating said choke valve, spring meansnormally tending to hold said choke valve inclosed position, whereby thesuction in said carburetor willbe simultaneously concentrated on both ofsaid nozzles, a suction passage connected at a point below said throttleto convey suction to operate said piston, and a yalve carried by saidpiston for controlling said suction passage.

3. In a carburetor, means forming an air passageway. a choke valve atthe inlet end of said passage, a throttle valve at the outlet end 0! 4said passage, a pair of fuel nozzles discharging by suction into saidair passageway, one of said nozzles discharging adjacent said throttle,and the other discharging between said throttle and said choke valve, asuction operated piston for operating said choke valve, heat responsivemeans yieldably tending to hold said choke valve in closed position whenthe temperature is low,

valve for controlling the admission of air to said conduit, said chokevalve including a part which is movable toward open position by directaction of suction, a suction operated piston connected to said choke insuch a manner as to tend to open the choke upon increases of suction,and a thermostat connected to said choke.

5. In a carburetor, means forming a mixing conduit, a plurality ofventuris in saidmixing conduit, a main. fuel nozzle discharging into oneof said venturis, a throttle controlling the discharge of mixture fromsaid carburetor, a second, fuel nozzle discharging into said mixingconduit adjacent said throttle valve, a choke valve for controlling theadmission of air to said conduit, said choke valve including a partwhich is movable toward open position by direct action of suction, asuction operated piston connected to said choke in such a manner as totend to open said choke upon increases in suction, a thermostatconnected to said choke, said thermostat being connected to said chokethrough a yieldable connection, whereby said thermostat may continue tomove after any stoppage of the movement of said choke valve.

6. In a plain tube carburetor, means forming a mixing conduit, meansforming a venturi in said mixing conduit, a main fuel nozzle discharginginto said venturi, a throttle controlling the discharge of mixture fromsaid carburetor, a

second fuel nozzle discharging into said mixing conduit adjacent saidthrottle valve, a choke valve for controlling the admission of air tosaid conduit, said choke valve including a part which is movable towardopen position by direct action of suction, a suction operated pistonconnected to said choke in such a manner as to tend to open said chokeupon increases in suction, a thermostat connected to said choke, saidthermostat being connected to said choke through a yieldable connection,whereby said thermostat may continue to move after any stoppage of themovement of said choke.

'7. In a carburetor, means forming a mixing conduit, a choke valvecontrolling the admission of air to said mixing conduit, said chokevalve having a part which is movable toward open position by directaction of suction, suction operated means for' opening said choke valvea lim-- ited distance only, said suction operated means beingconstructed and arranged to permit a connected to said choke valve tocontrol the same in ,said suction operated means being constructed andarranged to permit the continued opening movement of said choke to fullopen position, and

' means utilizing the direct action of suction for continuing theopening movement of said choke valve after said suction operated meanshas ceased operating.

9. In a carburetor, means forming a mixing conduit, a. choke valve forcontrolling the admission of air to said conduit, said choke valvecomprising a stem, a portion rigid'with said stem,- and a portionmovable with respect to said rigid portion and adapted to be directlyoperated by suction, and additional means operated by the suctionexisting in the outlet end of the mixing conduit for controlling therigid portion of said choke valve.

10. In a carburetor, means forming a mixing conduit, a choke valve forcontrolling the admission of air to said conduit, said choke valvecomprising a stem, a portion rigid with said stem, and a portion movablewith respect to said rigid portion and adapted to be directly operatedby suction, additional means operated by the suction existing in theoutlet end of the mixing conduit for controlling the rigid portion ofsaid choke; valve, and means including a heat responsive device forcontrolling the mixture delivered by said carburetor, I

11. In a carburetor, means forming a mixing conduit, a choke valve forcontrolling the admission of air to said conduit, said choke valvecomprising a stem, a portion rigid with said stern, and a portionmovable with respect to said rigid portion and adapted to be directlyoperated by suction, additional suction operated means for controllingthe rigid portion of said choke valve, and latch means controlled inaccordance with the position of the solid portion of said choke valvefor limiting the movements of that portion of the choke valve which isdirectly operated by suction.

12. In a carburetor, means forming a mixing conduit, a choke valve forcontrolling the admission of air to said conduit, said chokeyalvecomprising a stem, a portion rigid with said stem,

and a portion movable with respect to said rigid portion and adapted tobe directly operated bysuction, additional suction operated means forcontrolling the rigid portion of said choke valve, latch meanscontrolled in accordance withithe position of the solid portion of saidchoke valve for limiting the movements of that portion of the chokevalve which is directly operated by suction, and means including a heatresponsive device for controllingthe mixture delivered by saidcarburetor. v

13, In a carburetor, means forming a mixing conduit, a choke valve forcontrolling the admission of air to said conduit, said choke valvecomtinuance oi the opening of said choke valve after the cessation ofmovement of said suction operated means, and-a heat responsive elementconprising a stem, aportion rigid with said stem, and a portion movablewith respect to said rigid portion and-adapted to be directly operatedby suction, additional suction operated means for controlling the rigidportion of said choke .valve, and a heat responsive element foroperating said choke valve in conjunction with said suction operatedmeans.

sponsive element for-controlling the position of i said choke valve,suction operated means carried by said choke valve for admitting air bysuction when said choke valve is completely closed, and means inaddition to said suction operated means for automatically openingsaid'choke valve a predetermined degree whenever said engine is runningunder its own power. I

15. In a plain tube carburetor, means forming a mixing conduit, athrottle at the outlet of said conduit, a choke valve for controllingthe admission of air to said conduit, a heat responsive device connectedto the operating shaft of said choke valve, a suction responsive deviceconnected to the operating shaft of said choke valve and operated by thesuction existing in the outlet of said mixing conduit, one of saiddevices being free to move in one direction only with respect to saidshaft, and the other of said devices being rigidlyv connected to saidshaft, said mixing conduit anterior to said throttle being open and ofconstant size regardless of suction when the normal operatingtemperature is maintained or exceeded.

16. In a device of the class described, a choke valve, a shaft forsaid'choke valve, said choke valve comprising a portion solidly fixed tosaid shaft and a suction operated portion, means controlled by theposition of said shaft for limiting the movement of said suctionoperated portion, means comprising a suction responsive element and aheat responsive element for controlling the position of said shaft, saidsuction responsive element being adapted to initiate an opening movementof said choke valve, and said heat responsive element being constructedand arranged to complete the opening movement of said choke valve.

17. In a carburetor for internal combustion engines, an air passage, athrottle valve and a choke valve in said passage, said choke valvecomprising a plurality of portions, one of said portions being suctionoperated, a shaft rigidly fixed to another of said portions, a pistonconnected'to said shaft, a cylinder for said piston communicating withsaid air passage posterior tosaid throttle, and a heat responsive deviceconstructed and arranged to act in opposition to the opening of thechoke valve when the temperature is low.

18'. In a carburetor for internal combustion engines, an air passage, athrottle valve and a choke valve in said passage, said choke valvecomprising a plurality of portions, one of said portions being suctionoperated, a shaft rigidly fixed to another of said portions, a pistonconnected to said shaft, a cylinder for said piston communicating withsaid air passage posterior to said throttle, and a heat responsivedevice con--.

structed and arranged to act in opposition to the opening of the chokevalve when the temperature is low, said mixing conduit anterior to saidthrottle being open and of constant size regardless of suction when thenormal operating temperature is maintained or exceeded.-

19. In combination with an internal combustion engine, a plain tubecarburetor having a mixing conduit, a choke valve, and a throttle valvefor said conduit, temperature responsive means yieldingly urging thechoke valve toward closed position when the temperature is low, andsuction operated means capable of moving the valve to at least apartially opened position against the force of the temperatureresponsive means, said mixing conduit between I said choke and saidthrottle being open and of fixed size regardless of suction, said chokevalve being moved to fully open position when the normal operatingtemperature is reached or exprising a suction operated portion and asolid portion, a shaft rigidly fixed to said solid portion, a pistonconnecting with said shaft, a cylinder for said piston, a connection forconveying suction to said cylinder from a point in said air passageposterior to said throttle, and' a heat responsive device constructedand arranged to urge the choke valve toward fully open position when thetemperature is high.-

21. In a carburetor for internal combustion engines, an air passage, athrottle valve adjacent the posterior-end thereof, a choke valveadjacent the anterior end thereof, said choke valve comprising asuction. operated portion and a solid portion,.a shaft rigidly fixed tosaid solid portion, a piston connecting with said shaft, a cylinder forsaid piston, a connection for conveying suction to said cylinder from apoint in said air passage posterior to said throttle, and a heatresponsive device constructed and arranged to urge the choke valvetoward closed position whenthe temperature is low.

22. In a carburetor, an induction passage having an air inlet, a chokevalve controlling the air inlet, a throttle controlling the inductionpassage, a bimetallic spring thermostat having a resilient connectionwith the choke valve and adapted to close the choke valve when cold andto completely open it when hot, a suction chamber connected to theinduction passage posterior I to the throttle and having a movable wallresponsive to suction therein, yielding means urging said wall in adirection opposite to the force exerted on it by suction, and a one-wayactuating connection between the wall and the choke valve.

23. In combination with an internal combustion engine, a plain tubecarburetor having a choke valve, temperature responsive means yieldinglyurging the choke valve toward closed position when the temperature islow, and suction

